Donald Bren is a curious and contradictory figure in the world of philanthropy. Sole owner of the Irvine Company — responsible for building out a large part of sprawling Orange County, California — Bren is simultaneously the country's wealthiest real estate developer and one of its most celebrated conservationists.

He has both railed against environmental regulations and been hailed by former Governor Schwarzenegger for his environmental contributions. How has Bren managed such a feat? While building thousands of acres of housing, he's also built a legacy upon massive philanthropy.

Bren, 80, saw his fortune climb even higher in the past year, bringing his net worth up to $13 billion and making him the 26th richest man in the country. He made that wealth through the purchase and development of valuable land next to the coast of Southern California, becoming one of the most powerful and influential practitioners of suburban growth starting in the 1970s.

But along the way, he's also become known for tremendous philanthropy. Bren has given more than $1.3 billion away at last estimate, earning him a number of awards and recognitions for his generosity. He contributes to education, notably giving hundreds of millions to K-12 schools and University of California system, as well as research, the arts, and conservation.

Perhaps his best-known project, emblematic of how he's combined development and conservation, is his work in the Irving Ranch area of Orange County. Irvine Ranch is a 93,000-acre tract of land that makes up about a fifth of the county and runs between the Pacific Ocean to Cleveland National Forest. Irvine Co. has owned the land for decades, and since Bren started taking control of the company in 1977, it has been developed into affluent housing, office buildings, and shopping centers for cities like Laguna Beach, Irvine, and Newport Beach.

But while building out and retaining rights to about half of Irvine Ranch, Bren has handed over the remaining 50,000 acres of land to the public to be permanently protected as open space. The gift was widely celebrated for protecting ecologically important grasslands, woods, and canyons.

A notoriously private figure who offers rare interviews and appearances, Bren has certainly drawn his share of controversy, and the dual nature of his impact on the landscape has not been lost on Orange County. But whether for the land he's developed or the land he's protected, Bren has made a permanent impact on Southern California.